1. Field of the Invention
The present invention relates to a material presentation device which is equipped with a photographing section and an image displaying section, wherein at least two material presentation devices perform communications of images with each other and share images which are displayed on the image displaying sections.
2. Description of the Related Art
In recent years, material presentation devices have been widely used as image displaying devices for presentations instead of OHPs (overhead projectors). These material presentation devices are used so that a photographing section, which is equipped with a camera, photographs a material, and the image photographed by the photographing section is projected onto a monitor and a screen as a reference image. In this case, documents and pictures can be used as materials as they are, and three-dimensional objects, for example, models, can be used as objects. The material presentation devices are thereby much more useful than OHPs. Some of material presentation devices can receive images from external devices, for example, personal computers, and can output the images.
In a presentation, generally, a presenter often gives an explanation by indicating a specific part of a reference image with a pointer. In this case, the presenter performs a pointing operation on an image, which is output by an external device, either by using the external device on the side thereof (for example, operating a pointer with a mouse when using a personal computer) or by directly indicating a part of a display image on a monitor or a screen. In the former case, however, the operation is performed away from a material presentation device, thereby being troublesome. The latter case is not preferable since the view of the display image is blocked. To overcome the above problems, a method, in which a photographing section photographs the state in which a pointing operation is performed and a point image is synthesized with an external image which is output by an external device, is disclosed in Japanese Patent Unexamined Application Publication No. 2000-341588. A material presentation device, which is of increased value by the above method, is disclosed in Japanese Patent No. 3201707.
In meetings or in educational presentations, for example, communications and discussions are given with reference to common images between two persons who are far away from each other. Material presentation devices are under consideration as tools, which are used in the above cases, for mutual communications of images. In this case, if indicating marks or underlines were added to the images, it may be easy to understand the communications and may be flexible to have communications. It may be possible to add another image to the images by an image synthesizing function such as of the material presentation devices which are disclosed in the above publications. These material presentation devices, however, simply output and display a synthesized image, whereby it is not possible for two or more material presentation devices to be used so that these devices repeatedly synthesize additional images with each other and share synthesized images each time. The above function may be executed by adding exclusive image processing devices thereto, whereby, however, the system in which these devices are used is complicated, and the operations thereof are troublesome. In addition, the system incurs high cost due to the exclusive image processing devices.
Thus, it was supposed that the material presentation devices may be equipped with an image synthesizing section, and communicate and share a synthesized image among each other. In this system, however, capacities for image data which is communicated with each other are large, whereby communications and displaying images are time consuming, and these actions may not be executed smoothly.